New images reveal what NASA learned from colliding a spacecraft into an asteroid
Recent images released from NASA have revealed new information on the origins of the asteroid system.
Nearly two years ago, the Double Asteroid Redirection Test spacecraft, or DART, collided with Dimorphos, a small asteroid that is the moon of a bigger space rock, Didymos, at about 14,000 miles per hour, testing a strategy to defend against a potential asteroid headed toward Earth.
In a slate of studies published this week, NASA researchers have suggested that the mission did far more than accomplish its initial goal.
The five papers, published in the journal Nature Communications, have provided information on the origins, physical characteristics and evolution of the asteroids and are helping scientists gain a greater understanding of binary asteroid systems like planet asteroid Didymos and moonlet Dimorphos.
"These findings give us new insights into the ways that asteroids can change over time," Thomas Statler, lead scientist for Solar System Small Bodies at NASA Headquarters in Washington, said in a statement.
He went on, "This is important not just for understanding the near-Earth objects that are the focus of planetary defense, but also for our ability to read the history of our Solar System from these remnants of planet formation. This is just part of the wealth of new knowledge we've gained from DART."
In one study, researchers from the Johns Hopkins Applied Physics Laboratory in Maryland studied the geology of the asteroids. They found Didymos was smoother at lower elevations, rockier at high elevations and had more craters while the moonlet Dimorphos had boulders of varying sizes.
The team concluded that Dimorphos likely spun off from Didymos in what is known as a "large mass shedding event," which are natural processes that speed up the spinoff of smaller asteroids.
The team's analysis suggested Didymos has a surface age between 40 and 130 times older than Dimorphos with the former estimated to be 12.5 million years old and the latter less than 300,000 years old, NASA said.
Because Dimorphos' surface is younger, it likely had "low strength" which, in turn, contributed to why DART was so successful in disrupting its orbit.
In another paper, researchers compared the shapes and sizes of the boulders on the two asteroids and determined Dimorphos likely formed in stages with material from Didymos, providing further evidence that the former spun off from the latter.
A third study compared the boulders on Dimorphos to rubble pile asteroids -- asteroids that are made up of pieces of debris -- and found they shared similar characteristics, concluding all the asteroids likely formed similarly.
"The images and data that DART collected at the Didymos system provided a unique opportunity for a close-up geological look of a near-Earth asteroid binary system," Dr. Oliver Barnouin, a planetary geophysicist from Johns Hopkins APL, said in a statement. "From these images alone, we were able to infer a great deal of information on geophysical properties of both Didymos and Dimorphos and expand our understanding on the formation of these two asteroids. We also better understand why DART was so effective in moving Dimorphos."
